Actuating and control system for a pressure fluid operated track displacement apparatus



Sept. 10, 1963 F. PLASSER ETAL 3,103,182

ACTUATING AND CONTROL SYSTEM FOR A PRESSURE FLUID OPERATED TRACKDISPLACEMENT APPARATUS Original Filed May 26, 1959 2 Sheets-Sheet l1 INV EN TOM 23,! A/ L 1 1. A :5 8 BY 15:5 77 51/4254? p 1963 F. PLASSEREI'AL 3,1

ACTUATING .AND CONTROL SYSTEM FOR A PRESSURE FLUID OPERATED TRACKDISPLACEMENT APPARATUS Original Filed May 26, 1959 2 Sheets-Sheet 2INVENTOR. F R A11 2 PLkSS ER BY Jose? 8 United States Patent Office3,103,182 Patented Sept. 10, 1963 ACTUATING AND CONTROL SYSTEM FOR APRESSURE FLUID OPERATED TRACK DIS- PLACEMENT APPARATUS Franz Plasser andJosef Theurer, both "of Johannesgasse 3, Vienna, Austria Continuation ofabandoned application Ser. No. 815,979,

May 26, 1959. This application Nov. 8,1960, Ser- Claims priority,application Austria May 28, 1958 Claims. (Cl. 1047) The presentinvention relates to a pressure fluid operated apparatus for verticallydisplacing a track to a predetermined position. More particularly, thisinvention relates to an automatic actuating and control system foroperating the apparatus.

Apparatus mounted on a car movable over a track and adapted to move atrack section into a desired position is known. The desired position isfirst determined by a surveying team or a single surveyor and theapparatus is then operated, for instance by pressure fluid means, tomove the track section to the predetermined position.

It is the primary object of the invention to control the operation ofthe apparatus automatically so that the attention of the operator is notrequired for this purpose.

If such an automatic actuating and control system is used for a tracklifting apparatus mounted on a mobile track tamper, the track sectionmay be lifted to the desired level and fixed at such level by tampingballast under the adjacent tie, thus adding a further step in therecently developed automation of railroad track maintenance. Obviously,the efliciency of such modern railway maintenance machines will beincreased considerably if the obtention of the desired lifting strokerequires no special attention but is automatically controlled.

In accordance with our invention, the stroke of a pressure fluidoperated track displacing apparatus is controlled by the pressure in thefluid supply line to the apparatus, the sudden pressure increase at theinception of the track displacement stroke initiating means forcontrolling the continued pressure fluid supply to the apparatus.

According to a preferred embodiment of the invention, control means forthe supply of the pressure fluid is electrically actuated, the electricactuating circuit being closed in response to a predetermined pressurein the pressure fluid supply line and preferably including auto maticmeans for controlling the continued flow of pressure fluid to theapparatus. The inception of the track displacement stroke is alwaysaccompanied by the sudden increase in fluid pressure since added forceis necessarily needed to move the track.

In principle, therefore, the invention makes use of this clearly setmoment of inception of the displacement stroke, which causes a suddenpressure rise, to control the extent of the stroke. This may obviouslybe done by various control means, such as, for instance, the regulationof pressure fluid supply to the track displacement apparatus. In apreferred embodiment, an --adjustable time-delay relay is connected inthe electric actuating circuit, the relay being energized in response tothe sudden rise in' pressure at the inception of the track displacementstroke and, after the set time delay, opening the actuating circuit todiscontinue further pressure fluid supply to the apparatus.

The time'delay relay may be empirically adjusted or a suitable time ordisplacement distance scale may be provided for setting the relay. Insuch a case, the operator need only set the relay according to thedesired displacement stroke, i.e. the vertical positioning determined bythe surveyor, and the displacement stroke will be actuated andcontrolled entirely automatically and entirely independently from theheight of the roadbed upon which a portion of the track displacementapparatus bears.

The control system of the present invention makes it possible to makeuse of known means of automation to increase its efliciency evenfurther. For instance, the track position may have been determinedbeforehand graphically or by a punch card system by an advance surveyingcar. The results ofthese measurements may then be fed, for instance fromsuitable punch cards, to the control system of the presentinvention bydevices well known in the art of automation, the track displacementapparatus with its actuating and control system being mounted on a carwhich follows the advance car.

If a time-delay relay is used, for instance, to control the trackdisplacement stroke, it may be adjusted by a known control deviceresponsive to information stored in punch cards so that this operation,too, is automatically performed without an operators intervention, thepunch card automatically setting the relay adjustment means. A pressurefluid supply control means may be regulated in the same manner as thetime-delay relay.

Obviously, the punch cards produced by the advanced "surveying car mayalso be used automatically to halt the track positioning car at thedesired track section so that the original surveying results may be.used to control the correction of any track section fully automatically.

The above and other objects, advantages and features of the presentinvention will appear more fully fromthe following detailed descriptionof certain specific embodimerits thereof, provided merely forpurposes ofillustration and without in any way limiting the scope of the invention.In the accompanying drawing,

FIG. lis a sectioal front view of a track lifting apparatus; and

FIG. 2 is a schematic view of a control system accord ing to theinvention for track lifting apparatus of the general type illustrated inFIG. 1.

Referring now to the drawing, FIG. 1 illustrates one embodiment of atrack lifting apparatus which may be operated by the control system ofthe present invention. As shown, ballast '52. constitutes the roadbedfor a rail road track consisting of ties 51 and rails 1. A car frame 48is adapted to run on the track on wheels 49 which are mounted on axle 50journaled in webs 48'. Each web 48" carries a track lifting apparatuswhich may be laterally pivoted between an operative and a rest positionremoved from the track. The lifting apparatus includes a pressure fluidoperated jacking means comprising a cylinder 4 carrying at its lower enda laterally extending rail lift member 2 fixedlyattached to the liftcylinder and adapted to subtend and support rail 1 when the jackingmeans is in the operative position illustrated in full lines inIFIG. 1.Lift cylinder 4 has an upwardly ex tending lug 8 to support the cylinderpivotally on bracket 7 which extends laterally inwardly from web 48'. Inthis manner, the lift cylinder is pivotal about fulcrum 8 in a verticalplane transverse to the direction of the track, the pivoting axis of thejacking means being substantially parallel to the track.

Piston 5 with its piston rod 6 is slidablyguided in lift cylinder4, theouter end of the piston rod extending downwardly from the lift cylinderand carrying a foot pressure fluid, such as a hydraulic liquid, to theupper cylinder chamber whereby the piston may be forced downwardlyagainst the spring bias. The pressure fluid supply and control systemfor the operation of the acking means is shown in FIG. 2 and will bedescribed in connection therewith.

The jacking means 2, 3, 4, is laterally pivotal out of the range of thetrack to enable the car to move from track tie to track tie withoutinterference from the jacking means. One such pivoting means is shown inFIG. 1 and will be described hereinbelow.

The pivoting means includes a cylinder 9 slidably supporting a piston 12with its piston rod 13'. A conduit (not shown) supplies pressure fluid,such as a hydraulic liquid or compressed air, to one chamber of thecylinder 9 while the opposite chamber houses spiral compression spring9' to bias the piston inwardly. The outer end of the piston rod 13 islinked to a laterally extending lug of lift cylinder 4. Similarly tolift cylinder 4-, cylinder 9 also has an axially extending lug 11pivoted at 11 to'support 10 which is fixedly mounted on car frame 48. Inthis manner, the pivoting cylinder 9 is able to follow the pivotingmovement of lift cylinder 4 when the pivoting means is in operation, therest position of the jacking means with the corresponding position ofthe pivoting means being indicated in FIG. 1 in broken lines.

As will be obvious from the above description of the track liftingapparatus, supply of pressure fluid to the upper cylinder chamber oflift cylinder 4 will press foot piece 3 against the roadbed when thejacking means is in operative position. Since the rail lift member 2subtends the rail '1 in this position of the jacking means, it willsupport and lift the rail as the lift cylinder moves upwardly under thepressure of the continuing pressure fluid supply. After the track hasthus been lifted to and positioned at the desired level, the pres-surefluid is removed from the lift cylinder as well as from pivotingcylinder 9. This will cause spring 4 to move foot piece 3 out ofengagement with ballast 52 while compression spring 9 will cause theinward movement of piston rod 13 and the concomitant lateral pivoting ofcylinder 4 about fulcrum 8 into the rest position illustrated in brokenlines.

A specific embodiment of the control system for supplying pressurefluid, such as a hydraulic liquid, to the track lifting cylinder isillustrated schematically in FIG. 2. 'In principle, the trackdisplacement apparatus partially shown in FIG. 2 is similar to the tracklifting apparatus of FIG. 1, the specific track lifting structure shownin FIG. 2 being described more completely in our copending applicationNo. 815,982, filed May 26, 1959.

Basically, the track lifting apparatus of FIG. 2 differs from that ofFIG. 1 only by being pivotal outwardly of rail 1 instead of inwardlythereof. Corresponding to the cylinder 4 and lift member 2 in theembodiment of FIG. 1, the pressure fluid operated jacking means of FIG.2 includes a cylinder 4a carrying at its lower end a laterally extendingrail lift member constituted by a platform 2a fixedly attached to thelift cylinder and adapted to subtend and support rail 1 when the jackingmeans is in the illustrated operative position. Lift cylinder 4a has anupwardly extending lug 8a to support the cylinder pivotally on bracket7a which extends laterally outwardly from a car frame (not shown indetail). In this manner, the lift cylinder is pivotal about fulcrum 8ain a vertical plane transverse to the direction of the track, thepivoting axis of the jacking means being substantially parallel to thetrack.

Piston 5a with its piston rod 6a is slidably guided in lift cylinder 4a,the outer end of the piston rod extend- 7 ing downwardly from the liftcylinder and carrying a foot piece 3a which engages and bears upon theroadbed ballast (not shown) in the operative position of the jackingmeans. Conduits 21 and 22 are connected to respec- 4 V tive ones of thecylinder chambers to supply pressure fluid, such as a hydraulic liquid,to the cylinder to move piston 5a in either direction. The pressurefluid supply and control system for the operation of the jacking meanswill be described hereinafter.

As in the embodiment of FIG. 1, the jacking means is laterally pivotalout of the range of the track. The pivoting means includes a cylinder90. slidably supporting a piston 12a with its piston rod Conduit 9asupplies pressure fluid, such as a hydraulic liquid or compressed air,to one chamber of the cylinder 9a while the opposite chamber housesspirall compression spring 9" to bias the piston outwardly. The outerend of piston rod 13a is linked to 'a laterally extending lug 14a oflift cylinder 4a at pivot 15a.

Similarly to lift cylinder 40, cylinder 9a also has an axially extendinglug 11a pivoted to bracket 10a which is fixedly mounted on the carframe. In this manner, the pivoting cylinder 9a is able to follow thepivoting movement of lift cylinder do when the pivoting means is inoperation. The operation of this track lifting apparatus issubstantially identical with that of FIG. 1.

As shown in FIG. 2, the control and actuating means for the trackdisplacement apparatus includes a storage tank holding a supply 16 ofhydraulic liquid, for instance oil, constant delivery pump 17 deliveringhydraulic liquid into conduit 18 at a uniform rate while conduit 19serves as a return conduit leading back into the storage tank. Anelectromagnetieal ly controlled slide valve 20 regulates the supply ofhydraulic liquid to respective chambers of track moving cylinder 4a. Inone position of the slide valve, conduit 18 is closed off from conduits21. and 22 leading to the cylinder chambers and the hydraulic liquidflows back through return conduit 19. In other alternate positions ofthe valve, conduit 18 is connected either with supply conduits 21 or 22.

An auxiliary return conduit 23 branches off conduit 18 and is providedwith an adjustable relief valve 24 to protectthe entire hydraulic systemagainst excessive pressure and to limit the maximal displacement strokeof track moving cylinder 4a.

Slide valve 20 is normally centered by a pair of springs 20, 20",- thecenter position of the valve corresponding to the rest position ofcylinder 441 seen in FIG. 2, in which both liquid supply conduits 21 and22 are shut off from conduit 18. The pair of electromagnets 25, 26 serveto move the slide valve into the respective supply positions forconduits 21 and 22. Magnet 25 receives its power from electric conductor27 which forms part of an electric circuit including quick-action orsnap switch 28 'actuatable :by push button 29. A power source 32, suchas an electric storage battery, supplies current to the switch by meansof electric conductor 31.

Switch 28 is also actuatable by electromagnet 30 which receives itspower from electric conductor 33. The power supply in conductor 33 iscontrolled by switch 34 which is actuated by an adjustable time-delayrelay 35. The desired time delay of relay 35 may be set by moving apointer 35 on a scale 36. Instead of indicating the desired time delayor the desired time for actuating the track displacement apparatus,scale 36 may be calibrated to show directly the desired displacementdistance. The latter calibration will considerably facilitate therequired reading by the operator.

Time-delay relay 35 receives current from power source 32 by means ofelectric conductor 37, in which there is provided switch 37. Switch 37is operated by the pressure in supply conduit 22 in the followingmanner:

A branch line 43 leads from supply conduit 22 to one chamber of cylinder38 which slidably supports piston 44) with its associated piston rod 39.The outer end of the piston rod, which extends from cylinder 38, islinked to one end of a two-armed lever 39' whose other end carries oneelement of switch 37. Movement of piston rod 39 accordingly moves thelever 39 about its fulcrum and thus opens orcloses-switch 37. Acompressionspringfl is mounted in the other chamber of cylinder 38 andnormally biases piston 40 downwardly so as to keep switch 37 in theillustrated open position. i 41 maybe-adjusted by turning hand wheel 42.When the pressure emanating from conduit 22 and transmitted into thelower chamber of cylinder 38 through line 43 surpasses the bias ofsprin'g 41, the piston '40 moves upwardly and thus causesthe switch 37to be closed.

ment apparatus,-as-illustrated in FIG. 2, operates as follows:

After the car carrying the track displacement cylinder -4a has beenmoved tothe track-section which is to be moved and the cylinder has beenpivoted into the illustrated operative position-by thepiston 12a in theman- 'ner described above in connection with FIG. 1, push button 29 ispressedto actuate snap switch 28. This closes the connection betweentrunk line *31 and conductor 27 so that electromagnet- "is energized andpushes the slide valve 20 toward the right as viewed in FIG. 2 into aposition in which conduit 18 is connected with conduit 22, and returnconduit 19 with conduit 21 whereby pump 17 delivers hydraulic liquidfrom supply 16 into the upper chamber of cylinder 4a. This causes thepiston 5a to be depressed, i.e. to be moved relatively to the trackengaging means 2a from one position in which the road engaging means 3ais spaced from the roadbed to another position wherein the (foot piece34 is in engagement with the roadbed ballast and then, upon furthersupply of pressure fluid, begins to move cylinder 4a with its raillifting member 2a upwardly to lift the track, the actual lifting strokeagainst the resistance of the track causing a considerable pressureincrease in the hydraulic liquid supply conduits.

The sudden increase in pressure in conduit 2-2 at the moment the actuallifting operation begins causes a corresponding increase of pressure inthe lower chamber of cylinder 38, thereby moving piston 40 upwardlyagainst the bias of spring 41. Thus, this pressure responsive actuatingmeans closes switch 37. Closing of switch -37 generates a signal whichcauses energization of the electrically operated time-delay relay 3 5and its set adjustment according to the position of pointer 35' on thescale 36 controls the time during which hydraulic liquid flows at thefixed output rate of pump 17 through conduit 22, and, accordingly, thelength of the track moving stroke of cylinder 4a. As soon as the setperiod of time-delay relay 35 has expired and rail 1 has been moved thedesired distance, the relay closes switch 34-, thereby energizingelectromagnet 30. Upon energization, electromagnet opens switch 28 tode-energize electromagnet 25 and permit slide valve 20 to return to itsspring-controlled rest position which cuts oil conduits 21 and 22 fromconduits 19 and .18 so that no further liquid is supplied to cylinder4a. Pump 17 then merely circulates the pressure fluid through conduit 18and back to supply 16 through return conduit 19. The pressure in conduit22 remains unchanged so that the cylinder 4w maintains the rail in thedesired position.

After the rail has been fixed in position, tor instance by tampingballast under a tie supporting the rail, switch 45 is operated bypushing button 46. This may be done manually by an operator orautomatically in response to a set automation cycle well known per seand forming no part of the present invention. Closing of switch 45causes the electromagnet 26 to be energized and to move slide valve 20toward the left as viewed in FIG.

The bias of spring 2, into a positionwherein conduit 18 is connectedwith 'conduit 21 whereby pressurefluid is supplied to the lower chamberof cylinder 4a. Thiswill cause raising Olf foot piece 3a fromengagementwith the roadbed and as soon as the foot piece is high enough to permitlateral pivoting of the-jacking means out of the range of the track,push button 46 may be released again to deenergize magnet 26 and topermit slide valve 20 toreturn to the illustrated center position. Thejacking means may now be pivoted away from the track to permit the carto move on to a subsequent track section to be displaced.

While the track displacement apparatus actuating and control system hasbeen described in connection with a specific embodiment, it will beobvious to the skilled in the art that many variations and modificationsare possible withoutdepartlng from the spirit and scopeof the inventionas defined in the appended claims.

Thisis acon-tinuation of our application Serial No.

815,979, filed May 26, 1959-, now abandoned.

What we claim is: 1. In a pressurefluid operated track displacementapparatus, comprising a pressure fluid, cylinder means including acylinder and a piston with an associated piston rod slidably' supportedin said cylinder, a track engaging means connected with said cylindermeans, and

I a pressure fluid conduit arranged to-supply pressure fluid to thecylinder for moving the cylinder means through a track displacementstroke: an actuating and control system for the pressure fluid supply,said system comprising a valve means in said pressure fluid conduit,said valve means having an open and a normally closed position, anelectric control circuit, a power source delivering electric current tosaid circuit, means for holding the valve means in the normally closedposition, electro-magnctic means connected in said circuit andenergizable by the current for moving the valve means from said normallyclosed into the open position, first switch means in the circuit, saidswitch means being actuatable to close the circuit for energization ofthe electromagnetic means, energization of the electromagnet meansbringing the valve means into the open position whereby pressure fluidis supplied to the cylinder, actuating means responsive to the sudden.pressure increase caused in the pressure fluid conduit by the inceptionof the track displacement stroke, a second switch means in said circuit,said second switch means being normally open and being closable by saidpressure increase responsive means: upon the said sudden pressureincrease, an adjustable time-delay relay in said circuit, said relaybeing energized upon closing of the second switch means, a third switchmeans in the circuit, said third switch means being normally open andbeing closable by said time-delay relay, means for adjusting the relayto a desired time lag, and means for opening the first switch means,said switch opening means being connected in the circuit and beingoperated when said third switch means is closed by the time-delay relay,opening of the first switch means causing de-energization of theelectro-magnetic means and return of the valve means into the normallyclosed position.

2. The actuating and control system for the pressure fluid supply for a.pressure fluid operated track displacement apparatus according to claim1, wherein said pressure fluid conduit comprises a first branchdelivering pressure fluid into a first chamber of said cylinder foreffectuating said track displacement stroke and a second branch line fordelivering pressure fluid into a second chamber of said cylinder formoving the cylinder means in a direction opposite to said stroke, saidvalve means being movable into a second open position for supplyingpressure fluid into said second cylinder chamber, secondelectro-magnetic means in said control circuit for moving the valvemeans into said second open position, and fourth switch means in saidcircuit, said fourth switch means being normally open and means forclosing said fourth switch means to energize the secondelectro-rnagnetic means.

3. In combination with a pressure fluid operated track lifting apparatusfor lifiting a track off a, roadbed, said apparatus being mounted on acar movable on the track and comprising a source of pressure fluid, acylinder mounted on the car, a piston slidably arranged in said cylinderfor movement relative to the track, a track engaging means fixedlyconnected to the cylinder for engagement with the track, a roadbedengaging means fixedly connected to the piston for movement relative tothe track engaging means from one position wherein the roadbed engagingmeans is spaced from the roadbed to another position wherein the roadbedengaging means is in engagement with the roadbed upon the relativemovement of the piston, and a conduit arranged to supply pressure fluidfrom the pressure fluid source to the cylinder for actuation of therelative movement of the piston, the pressure of the fluid in saidconduit increas ing upon engagement of the roadbed engaging means withthe roadbed: an actuating and control system for the pressure fluidsupply, said system including an actuating means responsive to theincreased pressure in the conduit prevaient'upon engagement of theroadbed engaging means with the roadbed, and a pressure fluid supplycontrol means actuated by the pressure-respon- 8 sive actuating meansfor delimiting the pressure fluid actuation of the relative movement ofthe roadbed engaging means in respect of the track engaging means.

4. In the combination set forth in claim 3, said source of pressurefluid including a pump having a substantially uniform rate of deliveryof said fluid, and said control means including timing means forlimiting said fluid supply to said cylinder.

5. In the combination set forth in claim 4, said control means includingvalve means in said conduit, said timing means being arranged to closethe valve means.

References Cited inthe file of this patent UNITED STATES PATENTS2,465,758 Sedgwick et al Mar. 29, 1949 2,499,072 McClure Feb. 28, 19502,674,231 Enickson Apr. 6, 1954 2,685,794 Hall et 'al. Aug. '10; 19542,736,268 Yohe Feb. 28, 1956 2,762,313 Sublett Sept. 11, 1956 2,789,541Gaspar et al. Apr. 23, 1957 2,985,147 Rockwell May 23, 1961 2,990,786Kershaw July 4, 1961 3,020,706 Hill Feb. 13, 1962 3,044,266 Svenson.i.-. July 17, 1962

1. IN A PRESSURE FLUID OPERATED TRACK DISPLACEMENT APPARATUS, COMPRISINGA PRESSURE FLUID, CYLINDER MEANS INCLUDING A CYLINDER AND A PISTON WITHAN ASSOCIATED PISTON ROD SLIDABLY SUPPORTED IN SAID CYLINDER, A TRACKENGAGING MEANS CONNECTED WITH SAID CYLINDER MEANS, AND A PRESSURE FLUIDCONDUIT ARRANGED TO SUPPLY PRESSURE FLUID TO THE CYLINDER FOR MOVING THECYLINDER MEANS THROUGH A TRACK DISPLACEMENT STROKE: AN ACTUATING ANDCONTROL SYSTEM FOR THE PRESSURE FLUID SUPPLY, SAID SYSTEM COMPRISING AVALVE MEANS IN SAID PRESSURE FLUID CONDUIT, SAID VALVE MEANS HAVING ANOPEN AND A NORMALLY CLOSED POSITION, AN ELECTRIC CONTROL CIRCUIT, APOWER SOURCE DELIVERING ELECTRIC CURRENT TO SAID CIRCUIT, MEANS FORHOLDING THE VALVE MEANS IN THE NORMALLY CLOSED POSITION,ELECTRO-MAGNETIC MEANS CONNECTED IN SAID CIRCUIT AND ENERGIZABLE BY THECURRENT FOR MOVING THE VALVE MEANS FROM SAID NORMALLY CLOSED INTO THEOPEN POSITION, FIRST SWITCH MEANS IN THE CIRCUIT, SAID SWITCH MEANSBEING ACTUATABLE TO CLOSE THE CIRCUIT FOR ENERGIZATION OF THEELECTRO-MAGNETIC MEANS, ENERGIZATION OF THE ELECTROMAGNET MEANS BRINGINGTHE VALVE MEANS INTO THE OPEN POSITION WHEREBY PRESSURE FLUID ISSUPPLIED TO THE CYLINDER, ACTUATING MEANS RESPONSIVE TO THE SUDDENPRESSURE INCREASE CAUSED IN THE PRESSURE FLUID CONDUIT BY THE INCEPTIONOF THE TRACK DISPLACEMENT STROKE, A SECOND SWITCH MEANS IN SAID CIRCUIT,SAID SECOND SWITCH MEANS BEING NORMALLY OPEN AND BEING CLOSABLE BY SAIDPRESSURE INCREASE RESPONSIVE MEANS UPON THE SAID SUDDEN PRESSUREINCREASE, AN ADJUSTABLE TIME-DELAY RELAY IN SAID CIRCUIT, SAID RELAYBEING ENERGIZED UPON CLOSING OF THE SECOND SWITCH MEANS, A THIRD SWITCHMEANS IN THE CIRCUIT, SAID THIRD SWITCH MEANS BEING NORMALLY OPEN ANDBEING CLOSABLE BY SAID TIME-DELAY RELAY, MEANS FOR ADJUSTING THE RELAYTO A DESIRED TIME LAG, AND MEANS FOR OPENING THE FIRST SWITCH MEANS,SAID SWITCH OPENING MEANS BEING CONNECTED IN THE CIRCUIT AND BEINGOPERATED WHEN SAID THIRD SWITCH MEANS IS CLOSED BY THE TIME-DELAY RELAY,OPENING OF THE FIRST SWITCH MEANS CAUSING DE-ENERGIZATION OF THEELECTRO-MAGNETIC MEANS AND RETURN OF THE VALVE MEANS INTO THE NORMALLYCLOSED POSITION.